您可以为您的 NFLPlayer 类提供每个值的私有字段，而不是向您的方法传递这么多 int 参数（容易混淆）：
public class NFLPlayer {
private final String name;
private int touchdowns;
private int passingAttempts;
private int completedPasses;
private int passingYards;
private int interceptions;
public NFLPlayer(String name) {
this.name = name;
}
// Method names start with a lower case character in Java
// The name should usually be an imperative 'do something' not a noun ('something')
// although there are exceptions to this rule (for instance in fluent APIs)
public double calculateQbRating() {
double a = (completedPasses / passingAttempts - 0.3) * 5.0;
double b = (passingYards / passingAttempts - 3.0) * 0.25;
// an AritmeticException will occur if passingAttempts is zero
double c = (touchdowns / passingAttempts) * 25.0;
double d = 2.375 - (interceptions / passingAttempts * 25.0);
return ((a + b + c + d) / 6.0) * 100.0;
}
public String getName() {
return name;
}
// setter for the touchdowns field
public void setTouchdowns(int value) {
touchdowns = value;
}
// TODO: add other setters for each private field
@Override
public String toString() {
return String.format("Player %s has QB rating %s", name, calculateQbRating());
}
}
您的应用程序（这不称为测试）：
class NFLApplication {
public static void main(String[] args) {
NFLPlayer playerStats = new NFLPlayer("johnson");
playerStats.setTouchdowns(2);
playerStats.setPassingAttempts(44);
playerStats.setPassingYards(285);
playerStats.setInterceptions(1);
playerStats.setCompletedPasses(35);
double qbRating = playerStats.calculateQbRating();
System.out.println(qbRating);
}
}
使用 JUnit 框架对您的 NFLPlayer 类进行测试（JUnit 通常默认包含在您的 IDE 中）：
public class NFLPlayerTest {
// instance of the class-under-test
private NFLPlayer instance;
// set up method executed before each test case is run
@Before
public void setUp() {
instance = new NFLPlayer();
}
@Test
public void testCalculateQbRatingHappy() {
// SETUP
instance.setTouchdowns(2);
instance.setPassingAttempts(44);
instance.setPassingYards(285);
instance.setInterceptions(1);
instance.setCompletedPasses(35);
// CALL
double result = playerStats.calculateQbRating();
// VERIFY
// assuming here the correct result is 42.41, I really don't know
assertEquals(42.41, result);
}
@Test
public void testCalculateQbRatingZeroPassingAttempts() {
// SETUP
// passingAttempts=0 is not handled gracefully by your logic (it causes an ArithmeticException )
// you will probably want to fix this
instance.setPassingAttempts(0);
// CALL
double result = playerStats.calculateQbRating();
// VERIFY
// assuming here that you will return 0 when passingAttempts=0
assertEquals(0, result);
}
}
这个测试类应该放在你的测试源目录中（通常在yourproject/src/test/yourpackage/）。它需要一些导入，这些导入应该可以在 IDE 中轻松解析，因为 JUnit 通常默认情况下可用。
要运行测试，请右键单击它并选择“运行测试”、“测试文件”等内容，具体取决于您使用的 IDE（IDE 是 Eclipse、NetBeans 或 IntelliJ 等开发工具）。您应该会看到一些测试输出，指示测试是成功（绿色）还是失败（红色）。进行此类测试很有用，因为它迫使您思考您的设计并编写更好的代码。 （可测试的代码通常比难以测试的代码更好）并且因为它会在新更改导致现有代码中的错误（回归）时向您发出警告。
编辑：
要创建两个具有不同统计数据的玩家，您必须创建两个实例（我添加了一个name 字段，以便我们更容易区分玩家）：
NFLPlayer player1 = new NFLPlayer("adams");
NFLPlayer player2 = new NFLPlayer("jones");
并给他们每个人自己的统计数据：
player1.setTouchdowns(2);
player1.setPassingAttempts(4);
player1.setPassingYards(6);
player1.setInterceptions(8);
player1.setCompletedPasses(10);
player2.setTouchdowns(1);
player2.setPassingAttempts(3);
player2.setPassingYards(5);
player2.setInterceptions(7);
player2.setCompletedPasses(9);
您甚至可以创建一个玩家列表：
List<NFLPlayer> players = new ArrayList<>();
players.add(player1);
players.add(player2);
然后您可以循环打印出所有玩家评分：
for(NFLPlayer player : players) {
// this uses the `toString` method I added in NFLPlayer
System.out.println(player);
}